Added ETag and Last-Modified support

lib/resmin.js

@@ -243,14 +243,65 @@ module.exports.middleware = function(backend, dirPath, options) {
 		contentType = mime.lookup(filename);
 		charset = mime.charsets.lookup(contentType);
 		acceptEncoding = req.headers['accept-encoding'] || '';
+
+		function pass(name) {
+			var o = Object.create(options);
+			o.path = name;
+			staticSend(req, res, next, o);
+		}
+
+		function sendGzipped(data) {
+			contentType = contentType + (charset ? '; charset=' + charset : '');
+			res.setHeader('Content-Type', contentType);
+			res.setHeader('Content-Encoding', 'gzip');
+			res.setHeader('Vary', 'Accept-Encoding');	
+			res.setHeader('Content-Length', data.length);
+			res.end(data, 'binary');
+		}
+
+		function gzipAndSend(filename, gzipName, mtime) {
+			gzipFile(filename, charset, function(gzippedData) {
+				gzipFileCache[gzipName] = {
+					'ctime': Date.now(),
+					'mtime': mtime,
+					'content': gzippedData
+				};
+				sendGzipped(gzippedData);
+			});	
+		}
 
         if (filename.substring(filename.length-3) === '.gz') {
             contentType = mime.lookup(filename.substring(0, filename.length-3));
             charset = mime.charsets.lookup(contentType);
-            fs.readFile(filename, function (err, data) {
-                if (err) throw err;
-                sendGzipped(data);
-            });
+			fs.stat(filename, function(err, stats) {
+				if (err || !stats.isFile()) throw err;
+
+				// create etag and compare
+				var etag = '"' + stats.ino + '-' + stats.size + '-' + Date.parse(stats.mtime) + '"';
+				var ifMatch = req.headers['if-match'] || req.headers['if-none-match'];
+				if (ifMatch == etag) {
+					res.send(304);
+					return;
+				}
+
+				// check modified since
+				var ifModifiedSince = req.headers['if-modified-since'];
+				if (ifModifiedSince) {
+					var req_date = new Date(ifModifiedSince);
+					if (stats.mtime <= req_date && req_date <= Date.now()) {
+						res.send(304);
+						return;
+					}
+				}
+
+				// no etag/modified since or file have been modified
+				res.setHeader('ETag', etag);
+				res.setHeader('Last-Modified', stats.mtime);
+				fs.readFile(filename, function (err, data) {
+					if (err) throw err;
+					sendGzipped(data);
+				});
+			});
         } else {
 
 			if (filename.substring(filename.length-5) === '.less') {
@@ -265,33 +316,7 @@ module.exports.middleware = function(backend, dirPath, options) {
 
             if (!~acceptEncoding.indexOf('gzip'))
                 return pass(filename);
-
-            function pass(name) {
-                var o = Object.create(options);
-                o.path = name;
-                staticSend(req, res, next, o);
-            }
-
-            function sendGzipped(data) {
-                contentType = contentType + (charset ? '; charset=' + charset : '');
-                res.setHeader('Content-Type', contentType);
-                res.setHeader('Content-Encoding', 'gzip');
-                res.setHeader('Vary', 'Accept-Encoding');	
-                res.setHeader('Content-Length', data.length);
-                res.end(data, 'binary');
-            }
-
-            function gzipAndSend(filename, gzipName, mtime) {
-                gzipFile(filename, charset, function(gzippedData) {
-                    gzipFileCache[gzipName] = {
-                        'ctime': Date.now(),
-                        'mtime': mtime,
-                        'content': gzippedData
-                    };
-                    sendGzipped(gzippedData);
-                });	
-            }
-
+
             fs.stat(filename, function(err, stat) {
                 if (err || stat.isDirectory()) {
                     return pass(filename);	

package.json

@@ -1,6 +1,6 @@
 {
     "name" : "resmin",
-    "version" : "0.0.5-2",
+    "version" : "0.0.6-1",
     "author" : "Marcus Ekwall",
     "description" : "All-in-one compressor/merger/minifier middleware for connect/express",
     "homepage" : "https://github.com/mekwall/node-resmin",